Calculating APL in PFS

[Alexandre Gayk-Lemay]

Hello all, I seek PFS advice from experienced PFS GMs and/or officials,

I recently got into an argument with another PFS GM about determining APL. My stance is that the Pathfinder Society Roleplaying Guild Guide (currently v7) stands as the sole source on this subject and that it trumps other sources. The first paragraph of "Determining Subtiers" is what I would use to determine APL in a PFS game:
"In order to determine which subtier a mixed-level group of PCs must play in, calculate the group’s average party level (APL). Divide the total number of character levels by the number of characters in the party. You should always round to the nearest whole number. If you are exactly at 0.5, let the group decide which subtier they wish to play."

My colleague's stance is that APL should be calculated according to rules on encounter design (found on this page):
http://paizo.com/pathfinderRPG/prd/gamemastering.html
notably, the following passage:
"Determine APL: Determine the average level of your player characters—this is their Average Party Level (APL for short). You should round this value to the nearest whole number (this is one of the few exceptions to the round down rule). Note that these encounter creation guidelines assume a group of four or five PCs. If your group contains six or more players, add one to their average level. If your group contains three or fewer players, subtract one from their average level."
According to my colleague, this position is espoused by many online GMs who use 2010 posts made by Mr.Joshua J Frost:
"Groups, tables, sessions, etc normally have to calculate APL and play the appropriate sub-Tier. So, even at level 1, if you were a table of 6 level 1 characters, your APL is still 2 and that means you still need to play sub-Tier 1-2." (conversation found here: http://paizo.com/paizo/messageboards/paizoPublishing/pathfinder/pathfinderS ociety/general/shoppingWithPrestigePoints&page=1#48)
As you can see, Mr.Frost's posts imply that APL should be calculated according to the information found in the section on Encounter Design.

It seems to me that the information on the Encounter Design page is mostly incompatible with the Pathfinder Guild Guide's prescription for calculating APL and determining subtiers. As such, it should not merely override Encounter Design rules for determining APL when necessary but replace those rules completely in the context of PFS.
In our small circle of players, a lot of GP for out-of-tier rewards are at stake: for a season 0-3 scenario, the guild guide would have a table made up of 4x level 2 adventurers, 1x level 1 adventurer and 1x level 3 adventurer (average 2 therefore APL 2) play low tier whereas my colleague would attribute them an APL of 3 (average 2+1(as prescribed by the rules on Encounter Design)) and allow them to choose their subtier.

Thank you in advance for your help, our Lodge's balance depends on these results!

P.S. In addition, we have a word/rule-lawyer or two who would argue that the wording in the guild guide, "In order to determine which subtier a mixed-level group of PCs must play in" implies that a group on non-mixed-level PCs are exempt from these rules, and a group of 6x level 2 adventurers would have an APL of 3 (as per Mr. Frost's recommendation) whereas a group including 4x level 2 adventurers, 1x level 1 adventurer and 1x level 3 adventurer would have an APL of 2 (as per the Guild Guide's recommendation). So basically I need a consensus as to whether PFS GMs should [always and only rely on Encounter Design rules to calculate APL] or [always and only rely on the Guild Guide for calculating APL in PFS].

[Taenia]

The guide has long since been updated. It is updated every year and sometimes more frequently if needed.

Guide to Organized Play Season 7 wrote:

In order to determine which subtier a mixed-level group
of PCs must play in, calculate the group’s average party
level (APL). Divide the total number of character levels by
the number of characters in the party. You should always
round to the nearest whole number. If you are exactly at
0.5, let the group decide which subtier they wish to play.
Starting with Season 4, scenarios are designed for six
characters and contain instructions on how to adjust the
scenario for four-character parties. When the APL of a table
is between two subtiers (like APL 3 for a Tier 1–5 scenario),
a party of four characters must play the lower tier without
any adjustments for party size. A party of five to seven
characters whose APL is between two subtiers must play
the higher tier with the four-character adjustment.
For scenarios written in Seasons 0 to 3, when the APL is
in between subtiers, a party of six or seven characters must
play the higher subtier. Parties with four or five characters
must play the lower subtier. In the fringe case where there
are no players that are high enough to have reached the
subtier level (such as a party of six 3rd level characters),
the group may decide to play down to the lower subtier.

[James Risner]

You don't use Encounter Design. You use the APL in the PFS guide.

If you have 6 1st level, it is (1+1+1+1+1+1)/6 = 1 and you determine which season and what to do based on the season.

[Gullyble Dwarf - Lvl 7 DM]

What others have said is how it's done.

Your friend's link is guidelines for GM's designing encounters for their home campaign.

Your other friends are way off base. Due to various abuses when GM's/Players were left to their own devices in prior seasons, PFS leadership has left no wiggle room in determining which tier must be played by a group (yes, yes, there's the fringe case where if noone is in the upper tier and average is between tiers and you have 6-7 players they may choose to play down). Overall I believe PFS is better for it; though, it's a shame such things are required.